Shimadzu Corporation

Jingwen Yao

Shigeki Kajihara

Matthew Kelly

A tag database establishment section converts, based on information such as an amino acid sequence of an identified peptide and m/z of a peak, a sequence tag indicating a partial sequence and information related to the tag into a database and creates a tag database. When MS2 spectrum information is obtained by measuring a target peptide, a sequence tag acquisition section executes, on the tag database, a search based on coincidence of the m/z of the peak and the like and extracts a sequence tag with high reliability. A peptide identification section performs, based on an amino acid sequence of the sequence tag, m/z of a precursor ion, and the like, a search by a sequence tag search method taking into account a post-translational modification or a variation and identifies a peptide.

Mass spectrometric data analyzing apparatus and analyzing method

To enable more reliable detection of ion peaks from mass spectral data. Ion peaks are detected from mass spectrum by the following steps. A step of acquiring mass spectral data made up of peaks which is acquired using a mass spectrometer, the peaks having mass-to-charge ratio and intensity information, a step of classifying the peaks in the acquired mass spectral data into a plurality of classes according to the intensity of the peaks, and a step of identifying the peaks as ion peaks or noise peaks based on the intensity information of the peaks which have been classified into the plurality of classes.

Peak detection method for mass spectrometry and system therefor

(EN) MS analysis, MSanalysis, . . . , MSanalysis for peptide mixture are sequentially executed to obtain respective mass spectra (S). At this time, an analysis in which precursor ion is changed or a different cleavage condition is set for the same precursor ion is performed plural times to put together peaks appearing in mass spectra that are obtained respectively. After the number of peaks is increased, a useful peak is extracted using commonality and complementarity of the peaks of MSspectrum and MSspectrum and classification is performed for each type of peaks extracted to obtain an appearance frequency for each classification (S, S). An evaluation score on whether the extracted peak is a product ion and on a terminal is calculated based on reliability and appearance frequency that are obtained in advance (S). The evaluation score is used in estimating sequence with the use of the extracted peak to decide and output, for example, the priority of sequence candidates (S, S).

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